For the installation of optical fiber communication systems it has been proposed to use a dedicated optical fiber cable known as an order wire which can be used during installation and maintenance of the system by the installing and maintenance company to test the system. Specifically at remote sites, engineers would connect to the order wire communication sets which include microphone and earphone whereby the engineers can communicate with each other.
Typically such communication sets operate on a half-duplex principle, i.e., one party talks while the other listens and vice versa. Also, only two parties can use the system at any one time. Finally, the received signal is not regenerated so that the range between sites is limited.
It is an object of the present invention to provide a communications set which overcomes one or more of the above disadvantages.